Field of the Invention
The invention relates to an inductive power transfer system for transferring electric energy to a vehicle, wherein the system comprises a wayside (primary side) electric conductor arrangement for producing an alternating electromagnetic field and for thereby transferring the energy to the vehicle and comprises a vehicle side (secondary side) receiving device for receiving the alternating electromagnetic field and for producing electric energy by magnetic induction. Furthermore the invention relates to a vehicle comprising the vehicle side receiving device. The invention also relates to an arrangement comprising the wayside electric conductor arrangement. In addition, the invention relates to a method of operating an inductive power transfer system for transferring electric energy to a vehicle. A method of manufacturing an inductive power transfer system for transferring electric energy to a vehicle is also part of the invention.
Description of Related Art
WO 2012/136303 A1 discloses a system for the contactless transmission of energy from a primary winding to a vehicle comprising a secondary winding which can be inductively coupled to the primary winding, discloses a method for detecting metal pieces in the system, discloses a method for positioning a vehicle, discloses a method for determining a direction and discloses a positioning control method, wherein the primary winding is arranged in a stationary manner and can be acted upon by an alternating current. A winding arrangement is arranged in a stationary manner, said winding arrangement having a first winding and a second winding, in particular wherein the winding arrangement is arranged centrally with respect to the primary winding, wherein the first and second windings are each composed of at least two part windings. The surfaces around which the part windings of a particular winding are wound are exposed to a magnetic flux generated by the primary winding and are spaced apart from one another, in particular in such a manner that no flux line of the flux generated by the primary winding passes through said surfaces together, wherein the part windings each have such a winding number and such a surface around which said part windings wind that the voltages of the part windings, which voltages are induced by the, in particular changing, magnetic flux of the primary winding are identical in magnitude, and in particular wherein the first winding is arranged rotated with respect to the second winding in such a manner that each part winding of the first winding is arranged inductively coupled to each part winding of the second winding.
For example, as disclosed in WO 2012/136303 A1, it has been proposed earlier to transfer electric energy to a vehicle in a contactless manner, by magnetic induction. One advantage is that no cable connection to the vehicle is required. On the other hand, the primary side electric conductor arrangement for generating the alternating electromagnetic field and the secondary side receiving device should be positioned vis-à-vis. Any lateral displacement compared to the optimum position or optimum range of positions reduces the efficiency of energy transfer. Another problem is the possibility of electrically conducting objects being in between the primary and secondary side of the inductive power transfer (IPT) system. In particular, metal objects, including metallized objects, will be rapidly heated during contactless energy transfer and might damage parts of the system, might injure people and/or might catch fire.
WO 2012/136303 A1 proposes a system including additional winding arrangements on both sides, the primary side and the secondary side, for position detection of the secondary side receiving device. An alternating voltage is applied to a first winding of the winding arrangement which is combined with the primary side electric conductor arrangement. The vehicle is steered into that direction where the amounts of voltages induced in part windings of the winding arrangement on the secondary side reach a maximum, wherein the induced voltages comprise a phase shift of essentially 180° relative to the alternating voltage.
This means that the position of the vehicle or of the secondary side receiving device is determined on the secondary side. On the other hand, as mentioned, winding arrangements are required on both, the primary side and the secondary side in addition to the devices which are necessary for the energy transfer.